1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4 */
5
6 #include <linux/blkdev.h>
7 #include <linux/slab.h>
8 #include <linux/buffer_head.h>
9
10 #include "exfat_raw.h"
11 #include "exfat_fs.h"
12
13 static const unsigned char free_bit[] = {
14 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/* 0 ~ 19*/
15 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~ 39*/
16 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~ 59*/
17 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~ 79*/
18 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~ 99*/
19 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/
20 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/
21 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/
22 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/
23 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/
24 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/
25 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/
26 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /*240 ~ 254*/
27 };
28
29 static const unsigned char used_bit[] = {
30 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/* 0 ~ 19*/
31 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~ 39*/
32 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~ 59*/
33 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~ 79*/
34 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~ 99*/
35 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/
36 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/
37 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/
38 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/
39 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/
40 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/
41 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/
42 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /*240 ~ 255*/
43 };
44
45 /*
46 * Allocation Bitmap Management Functions
47 */
exfat_allocate_bitmap(struct super_block * sb,struct exfat_dentry * ep)48 static int exfat_allocate_bitmap(struct super_block *sb,
49 struct exfat_dentry *ep)
50 {
51 struct exfat_sb_info *sbi = EXFAT_SB(sb);
52 long long map_size;
53 unsigned int i, need_map_size;
54 sector_t sector;
55
56 sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
57 map_size = le64_to_cpu(ep->dentry.bitmap.size);
58 need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
59 + 1;
60 if (need_map_size != map_size) {
61 exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
62 need_map_size, map_size);
63 /*
64 * Only allowed when bogus allocation
65 * bitmap size is large
66 */
67 if (need_map_size > map_size)
68 return -EIO;
69 }
70 sbi->map_sectors = ((need_map_size - 1) >>
71 (sb->s_blocksize_bits)) + 1;
72 sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
73 sizeof(struct buffer_head *), GFP_KERNEL);
74 if (!sbi->vol_amap)
75 return -ENOMEM;
76
77 sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
78 for (i = 0; i < sbi->map_sectors; i++) {
79 sbi->vol_amap[i] = sb_bread(sb, sector + i);
80 if (!sbi->vol_amap[i]) {
81 /* release all buffers and free vol_amap */
82 int j = 0;
83
84 while (j < i)
85 brelse(sbi->vol_amap[j++]);
86
87 kvfree(sbi->vol_amap);
88 sbi->vol_amap = NULL;
89 return -EIO;
90 }
91 }
92
93 return 0;
94 }
95
exfat_load_bitmap(struct super_block * sb)96 int exfat_load_bitmap(struct super_block *sb)
97 {
98 unsigned int i, type;
99 struct exfat_chain clu;
100 struct exfat_sb_info *sbi = EXFAT_SB(sb);
101
102 exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
103 while (clu.dir != EXFAT_EOF_CLUSTER) {
104 for (i = 0; i < sbi->dentries_per_clu; i++) {
105 struct exfat_dentry *ep;
106 struct buffer_head *bh;
107
108 ep = exfat_get_dentry(sb, &clu, i, &bh);
109 if (!ep)
110 return -EIO;
111
112 type = exfat_get_entry_type(ep);
113 if (type == TYPE_BITMAP &&
114 ep->dentry.bitmap.flags == 0x0) {
115 int err;
116
117 err = exfat_allocate_bitmap(sb, ep);
118 brelse(bh);
119 return err;
120 }
121 brelse(bh);
122
123 if (type == TYPE_UNUSED)
124 return -EINVAL;
125 }
126
127 if (exfat_get_next_cluster(sb, &clu.dir))
128 return -EIO;
129 }
130
131 return -EINVAL;
132 }
133
exfat_free_bitmap(struct exfat_sb_info * sbi)134 void exfat_free_bitmap(struct exfat_sb_info *sbi)
135 {
136 int i;
137
138 for (i = 0; i < sbi->map_sectors; i++)
139 __brelse(sbi->vol_amap[i]);
140
141 kvfree(sbi->vol_amap);
142 }
143
exfat_set_bitmap(struct inode * inode,unsigned int clu,bool sync)144 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
145 {
146 int i, b;
147 unsigned int ent_idx;
148 struct super_block *sb = inode->i_sb;
149 struct exfat_sb_info *sbi = EXFAT_SB(sb);
150
151 if (!is_valid_cluster(sbi, clu))
152 return -EINVAL;
153
154 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
155 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
156 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
157
158 set_bit_le(b, sbi->vol_amap[i]->b_data);
159 exfat_update_bh(sbi->vol_amap[i], sync);
160 return 0;
161 }
162
exfat_clear_bitmap(struct inode * inode,unsigned int clu,bool sync)163 int exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
164 {
165 int i, b;
166 unsigned int ent_idx;
167 struct super_block *sb = inode->i_sb;
168 struct exfat_sb_info *sbi = EXFAT_SB(sb);
169 struct exfat_mount_options *opts = &sbi->options;
170
171 if (!is_valid_cluster(sbi, clu))
172 return -EIO;
173
174 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
175 i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
176 b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
177
178 if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
179 return -EIO;
180
181 clear_bit_le(b, sbi->vol_amap[i]->b_data);
182
183 exfat_update_bh(sbi->vol_amap[i], sync);
184
185 if (opts->discard) {
186 int ret_discard;
187
188 ret_discard = sb_issue_discard(sb,
189 exfat_cluster_to_sector(sbi, clu),
190 (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
191
192 if (ret_discard == -EOPNOTSUPP) {
193 exfat_err(sb, "discard not supported by device, disabling");
194 opts->discard = 0;
195 }
196 }
197
198 return 0;
199 }
200
201 /*
202 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
203 * the cluster heap.
204 */
exfat_find_free_bitmap(struct super_block * sb,unsigned int clu)205 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
206 {
207 unsigned int i, map_i, map_b, ent_idx;
208 unsigned int clu_base, clu_free;
209 unsigned char k, clu_mask;
210 struct exfat_sb_info *sbi = EXFAT_SB(sb);
211
212 WARN_ON(clu < EXFAT_FIRST_CLUSTER);
213 ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
214 clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));
215 clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
216
217 map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
218 map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
219
220 for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
221 i += BITS_PER_BYTE) {
222 k = *(sbi->vol_amap[map_i]->b_data + map_b);
223 if (clu_mask > 0) {
224 k |= clu_mask;
225 clu_mask = 0;
226 }
227 if (k < 0xFF) {
228 clu_free = clu_base + free_bit[k];
229 if (clu_free < sbi->num_clusters)
230 return clu_free;
231 }
232 clu_base += BITS_PER_BYTE;
233
234 if (++map_b >= sb->s_blocksize ||
235 clu_base >= sbi->num_clusters) {
236 if (++map_i >= sbi->map_sectors) {
237 clu_base = EXFAT_FIRST_CLUSTER;
238 map_i = 0;
239 }
240 map_b = 0;
241 }
242 }
243
244 return EXFAT_EOF_CLUSTER;
245 }
246
exfat_count_used_clusters(struct super_block * sb,unsigned int * ret_count)247 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
248 {
249 struct exfat_sb_info *sbi = EXFAT_SB(sb);
250 unsigned int count = 0;
251 unsigned int i, map_i = 0, map_b = 0;
252 unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
253 unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;
254 unsigned char clu_bits;
255 const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,
256 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};
257
258 total_clus &= ~last_mask;
259 for (i = 0; i < total_clus; i += BITS_PER_BYTE) {
260 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
261 count += used_bit[clu_bits];
262 if (++map_b >= (unsigned int)sb->s_blocksize) {
263 map_i++;
264 map_b = 0;
265 }
266 }
267
268 if (last_mask) {
269 clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);
270 clu_bits &= last_bit_mask[last_mask];
271 count += used_bit[clu_bits];
272 }
273
274 *ret_count = count;
275 return 0;
276 }
277
exfat_trim_fs(struct inode * inode,struct fstrim_range * range)278 int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
279 {
280 unsigned int trim_begin, trim_end, count, next_free_clu;
281 u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
282 struct super_block *sb = inode->i_sb;
283 struct exfat_sb_info *sbi = EXFAT_SB(sb);
284 int err = 0;
285
286 clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
287 EXFAT_FIRST_CLUSTER);
288 clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
289 trim_minlen = range->minlen >> sbi->cluster_size_bits;
290
291 if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
292 return -EINVAL;
293
294 if (clu_end >= sbi->num_clusters)
295 clu_end = sbi->num_clusters - 1;
296
297 mutex_lock(&sbi->bitmap_lock);
298
299 trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
300 if (trim_begin == EXFAT_EOF_CLUSTER)
301 goto unlock;
302
303 next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
304 if (next_free_clu == EXFAT_EOF_CLUSTER)
305 goto unlock;
306
307 do {
308 if (next_free_clu == trim_end + 1) {
309 /* extend trim range for continuous free cluster */
310 trim_end++;
311 } else {
312 /* trim current range if it's larger than trim_minlen */
313 count = trim_end - trim_begin + 1;
314 if (count >= trim_minlen) {
315 err = sb_issue_discard(sb,
316 exfat_cluster_to_sector(sbi, trim_begin),
317 count * sbi->sect_per_clus, GFP_NOFS, 0);
318 if (err)
319 goto unlock;
320
321 trimmed_total += count;
322 }
323
324 /* set next start point of the free hole */
325 trim_begin = trim_end = next_free_clu;
326 }
327
328 if (next_free_clu >= clu_end)
329 break;
330
331 if (fatal_signal_pending(current)) {
332 err = -ERESTARTSYS;
333 goto unlock;
334 }
335
336 next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
337 } while (next_free_clu != EXFAT_EOF_CLUSTER &&
338 next_free_clu > trim_end);
339
340 /* try to trim remainder */
341 count = trim_end - trim_begin + 1;
342 if (count >= trim_minlen) {
343 err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
344 count * sbi->sect_per_clus, GFP_NOFS, 0);
345 if (err)
346 goto unlock;
347
348 trimmed_total += count;
349 }
350
351 unlock:
352 mutex_unlock(&sbi->bitmap_lock);
353 range->len = trimmed_total << sbi->cluster_size_bits;
354
355 return err;
356 }
357